This is a black and white woodcut illustration of a fantastical sea creature labeled 'Rosmarus'. The creature is large and elongated, resembling a cross between a whale and a lizard. It has a bulbous head with a long snout and small, beady eyes. A row of spiky fins runs along its back, and its body is covered in scales. The creature has four small legs with clawed feet. Its tail is thick and curled. The creature appears to be emerging from the water, with waves and splashes surrounding it. The style of the illustration is reminiscent of medieval or early modern bestiaries, with detailed linework and a focus on depicting the creature's monstrous features.